Interchangeable compass-point.



No. 889,447. PATENTED JUNE 2, 1908, J. EIGHMULLBR.

INTERGHANGEABLE COMPASS POINT. 1111101111011 111.1111 0012.11, 1907.

FIGJ. H62. FIGS.

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- UNITED STATES PATENT OFFICE.

JOHANN EIOHMULLER, OF NUREMBERG, GERMANY.

- INTERCHANGEABLE COMPASSPOI1\TT.

No. 889,447. Specification of Letters Patent. Patented June 2, 1908.Application filed October 11, 1907. Serial No. 396,946.

To all whom it may concern: j provided with a device for preventingrota- Be it known that I, JOHANN EIoHMi'ILLER, l tion of the needle andas shown said device of Nuremberg, in the Kingdom of Bavaria, I consistsof an integrally formed indented Germany, have invented new and usefulImportionf located on one side of the foot e and 5 provements inInterchangeable Compassprojecting a slight distance into the borePoints, of which the following is a specificathereof. A memberpreferably in the form tion. of a nut t is operatively associated withthe foot 6 and the needle in a manner which will This invention relatesto improvements in ad usting means for compass needles wherein I behereinafter more fully described and as 10 the needles are threaded andwherein an adshown said foot 6 is provided with a transjusting nut ormember is provided having versely disposed recess 6 to receive saidthreaded engagement with the needle for the member If. A bridge portion(2 unites the purpose of permitting longitudinal adj ustends of the foot0 which are divided by said ment of the latter, suitable devices beingprorecess 0 and conveniently said bridge porvided to lock said member ornut in its adtion forms a support for an instrumentality j ustedposition and to prevent rotation of the I serving to lock said nut tin'its adjusted poneedle during adjustment thereof by the nut. sitionand which instrumentality as shown In devices of this character theneedle is consists of a set screw 0. In order to afford usually of .avery small diameter and its an effective locking engagement between the75. 2 threads are easily mutilated and in adjusting set screw and saidnut the latter is roughmechanisms of prior constructions it has ened orserrated on its periphery as clearly been found impossible to lock theneedle in shown in Figs. 1 and 2. It will be seen that its adjustedposition without subjecting the recess 6 is so proportioned with respectthreaded portions thereof to injurious presto the nut 25 as to permit ofa relatively slight 25 sure against either the adjusting means or theplay or clearance between the nut and the compass foot in which theneedle is adjusted. lateral walls of said recess, the purpose of It isthe object of the present invention to J which construction willhereinafter more not only provide an improved device for prefullyappear. It will also be noted that the venting rotation of the needlesbut to pro- 7, disposition of the set screw 0 with respect to 30 vide anadjusting and holding means so con- 1 the indented portion f is suchthat when the maintain the needle in its adjusted position ter throughthe needle. without sub ectin the threads thereof to The com ass need eor oint is indicated pressure frorfi an ii nthreaded surface. at a andis PPTOVICIGCI with ai i engaging surface 35 The invention will be morefully described which in the form shown consists of a longiin connectionwith the accompanying drawl tudinally flattened portion (Z adapted to being and will be more particularly pointed out engaged by the indentedportion f to prevlent and ascertained in and by the appended rotation ofthe needle. Said needle is cy inclaims. l drical throughout its mainbody portion ex- -10 In the drawing :Figure 1 is a View in side cept forsaid flattened surface and is pro elevation of a compass leg equippedwith a t vided with screw threads on its cylindrical device embod in themain features of m ortion which are interru ted b said fiatinvention. 2is an inside face viexi j tbned surface. The threaded portion of saidthereof. Fig. 3 is a side elevation of the leg j needle is in threadedconnection with the nut 45 with sectional portions taken on line 3-3 oft Fi 2. Fig. 4 is a sectional view on line 44 of Fig. 3. j a fitsrelatively loosely in the bore of the foot Like characters of referencedesignate simi- I e and is provided therein with a clearance or larparts throughout the different figures of pllay sllghtly 11111 excess ofthe1 plfity agordefil 50 the drawin tie nut 25 in t e recess 6 an t e inente As shown A designates one leg of a comportion f projects into thebore of the foot e pass which is provided with needle receiving asufficient distance to normally prevent romeans xzihichhmay beiIhtllEfOInl p11" 1a foot e tation o' thedneeplle a xlxl hile the latte;is being provlde wit a centra y lspose ongltua uste an w en t e partsare ree. 55 dinal bore throughwhich theneedle is adapted After theoperator has ad usted the needle to be inserted. Said foot e isconveniently a by turning the nut 25 so that sald needle is t and isadapted to be longitudinally adjusted thereby in the bore of the foot e.The needle with a foot having a bore and in the desired position the setscrew 0 is fitting said recess with a clearance relatively turned untilit engages the nut t. The result of such engagement will be that the nutand needle will be moved bodily transversely to the longitudinal axis ofthe needle until the flattened surface I) engages the indented portionf. Said indented portion f will then act as a fulcrum for the needle andcontinued pressure from the screw 0 will swing the upper end of theneedle away from the leg A until the surface t of the nut 15 engages thelateral wall 6 of the recess e whereupon the parts will be securelylocked with the fiattened surface I) in engagement with the indentedportion f and the nut 15 in engagement with the wall of the recess 6 asdescribed. Of course the movement hereinbefore described will be almostinfinitesimal and the parts are so proportioned that such movement willnot be sufficient to bring the threaded portion a into engagement withthe unthreaded portion a of the bore in the foot e thereby protectingthe threaded portions of the needle a from injurious engagement withunthreaded portions of the foot e. It will thus be seen that a firm andrigid locking engagement of the needle can be effected withoutsubjecting any of its threaded portions to mutilating pressure. Suchpressure as may be imparted to threaded portions of the needle throughthe nut t will not as a matter of course be injurious because the nuthas threaded engagement with the needle.

By the provision of the integrally formed indented portion f applicantavoids not only the first cost but the subsequent annoyance and troubleattending the maintenance of movable means in properly adjustedpositions. The indented portion f is not only cheaply and easily formedin the foot 2 but it constitutes a convenient and effective stationarydevice for preventing rotation of the needle.

I claim 1. In combination, a compass leg provided an indented portionprojecting into said bore, said foot also having a transversely disposedrecess, a threaded compass needle fitting said bore with a limitedclearance and rovided with a flattened surface adapted for engagementwith said indented portion, a nut having threaded engagement with saidneedle and reduced with respect to the clearance afforded said needle insaid bore, and a set screw mounted in said foot and engaging said nutand acting therethrough to force the flattened surface of said needleinto engagement with .said indented portion and effect engagement ofsaid nut with said recess to lock said needle in its adjusted plpsitionand prevent engagement between t readed portions of said needle and thewall of said bore.

2. In combination, a compass leg, a threaded compass needle providedwith an unthreaded engaging portion, said leg being provided with meansfor receiving said needle and also with a device adapted to engage saidunthreaded portion to prevent rotation of said needle, a memberoperatively connected with said needle and associated with said meansfor effecting adjustment of said needle, and an instrumentalitycooperating with said member and acting therethrough to force saidunthreaded portion into engagement with said device, the parts being soarranged that said member will engage said means to lock said needle inits adjusted position without engagement between the threaded portionsof said needle and said means.

3. In combination, a compass leg provided with a foot having a bore andstationary integrally formed means for preventing rotation of a needle,said foot having a transversely disposed recess, a threaded compassneedle fitting said bore loosely and provided with a flattened surfaceadapted tobe engaged by said means, a nut having threaded engagementwith said needle and fitting said recess, and a set screw mounted insaid foot and engaging said nut to force said flattened surface intoengagement with said means, the parts being so arranged that engagementbetween said nut and recess andsaid flattened surface and means tolocksaid needle in its adjusted position will maintain the threadedportions of the needle out of contact with said foot.

In testimony whereof I affix my signature in presence of two witnesses.

J OHANN EICHMULLER.

Witnesses HEINRICH Fro'rrr, HERMAN DoHLEMANN.

